Interpretive Summary: There are ongoing environmental assessments using computer simulation models that require realistic plant growth description of functional groups in different regions. "Functional group" in this context is an operational term, based on similarities in plant type and in plant parameter values. Likewise, Plant Materials Centers of the Natural Resource Conservation Service of USDA are valuable resources, often overlooked and underutilized for plant evaluations in the different regions of the U.S. Our objectives of this study were to quantify some critical plant simulation values of representative plant species for some major plant functional groups in the western U.S. Working mainly with Plant Materials Centers we measured these values for plant growth during the growing season in established field plots. Plant species measured varied among sites and years. These plant parameters for the ALMANAC model were then used to simulate five representative ecological sites in the region. These plant parameters are valuable for simulating individual plant species and plant functional groups. Using these plant parameters, the ALMANAC model will be readily implemented for important environmental assessments. This model and similar models should prove to be valuable tools for Conservation Practice Planning.

Technical Abstract:
Regional environmental assessments with process-based models require realistic estimates of plant parameters for the primary plant functional groups in the region. “Functional group” in this context is an operational term, based on similarities in plant type and in plant parameter values. Likewise, Plant Materials Centers of the Natural Resource Conservation Service of USDA are valuable resources, often overlooked and underutilized for plant evaluations in the different regions of the U.S. With this in mind, the objectives of this study were to quantify leaf area index, light extinction coefficient for Beer’s law, radiation use efficiency, and nitrogen and phosphorus concentrations in well-managed stands of representative plant species for some major plant functional groups in the western U.S. Working mainly with Plant Materials Centers we measured fraction of intercepted photosynthetically active radiation, leaf area index, and dry matter during the growing season in established field plots. Plant species measured varied among sites and years. These plant parameters for the ALMANAC model were then used to simulate five representative ecological sites in the region. These plant parameters are valuable for simulating individual plant species and plant functional groups. Using these plant parameters, the ALMANAC model will be readily implemented to interpret site monitoring and guide adaptive management approaches. This model and similar models should prove to be valuable tools for Conservation Practice Planning.